Hoist



YFeb. 16, 1943'. M. E. HOVER r 2,311,544

HOIST Filed Oct. 2l, 1940 2 Sheets-Sheet l INVENTOIL, /70076 E. /fo Ver,

Byf ATTORNEY. A

Patented Feb. 16, 1943 UNITED STATES PATENT 'OFFICE HOIST Monte E. Hover, Culver City, Calif. Application October 21, 1940, Serial No. 362,002

11 Claims.

lVly invention relates in general to improvements in ladder hoists and more particularly to improved means for raising a pivoted rack such as that disclosed in the copending application of William G. Kuehn and myself, Serial No. 230,276, filed September 16, 1938.

In said copending application, there is disclosed a simple and economical form of hoist adapted for use with fire ladders, dump-truck bodies, etc. The device disclosed therein fullls the requirement for which it was designed, but to provide even greater eiliciency, I have designed the improvements disclosed herein.

It is a major object of my invention to provide a hoist which may be quickly and easily elevated to any desired position, and which is very strong and durable, although relatively light and simple in construction.

It is a further object of my invention to provide a means for automatically locking this hoist in any desired position, such locking means also eing applicable wherever it is desired to prevent a shaft or similar device from rotating unless it is under the direction and control of an operator.

These and other objects of my invention will become apparent from the following description of a preferred form thereof, and from the accompanying drawings illustrating that form, in which:

Fig. l is a side elevational view of the hoist with the rack in lowered position,

Fig. 2 is a plan view of the hoist,

Fig. 3 is an end view of the hoist with the rack in lowered position,

Fig. 4 is a cross-sectional view taken on dell in Fig. 2,

Fig. 5 is a View taken at 5-5 in Fig. 2, and showing the rack in lowered position in solid outline, and in raised position in dotted outline,

Fig. 6 is a cross-sectional View of my new and improved wheel looking device,

Fig. 'I is a cross-sectional view taken at 'I- in Fig. 2, and showing the rack link locking mechanism in unlocked position, and

Fig. 8 is a similar View showing the mechanism in locked position.

Referring now to the drawings, and particularly to Fig. l thereof, the numeral I indicates a framework which is rigidly attached to the frame of a means. A bed II is rotatably attached to the framework Ic, and a box-frame I2 is pivotally attached at the forward end I3 of upstanding members Iii and Ilia which are rigidly attached to the bed Il, as shown in my copending application. Box-frame I2 carries a ladder (not shown) and when in the horizontal or lowered position, the box-frame rests on stops I and I5@ formed by the rear portions of upstanding members I4 and Ida. Near the rear end of the bed` ire truck (not shown) by any suitable I I, upstanding ears I8 and Ia provide means for pivotally attaching a pair of swivel links Ii and Ila to the bed Ii; and at the free end of each link, a rack I8 and 18a is pivotally connected. A shaft IS, journaled into the box-frame I2 and extending transversely thereof, carries gears 20 and 2te on its ends, which mesh with the teeth on racks IS and ISa. At this stage, I have a boxframe I2 rotatable about a horizontal axis I3 and attached to the forward end of bed II by the upstanding members Id and Ida. Near the other or rear end of bed I I, I have a pair of rack members I8 and IBa pivotally attached by means of swivel links I'I and I'Ia to the u'pstanding ears I5 and Ia which are fast to the bed Il. The gears 2S and 20a engage the teeth on the racks I3 and Ida, and it will now be apparent that if the shaft I9 is rotated, the box-frame I2 will be rotated upwardly as the gears travel along the rack. To prevent any possibility of the racks I8 and Isa being disengaged from the gears 2i) and 29a. I provide straps 2i, 2Ia, 22, and 22a, adjacent the edges of the gears, and I join the upper ends of the straps with rollers 23 and 23a which ride on the upper surfaces of the racks I8 and |80.. In this way the racks are held in engagement with the gears at all times.

When using this hoist to elevate a long ladder, such as may be done in the case of iire equipment, the force exerted on the hoist at the point of the shaft I9 may be quite large; and in addition, when threading the-ladder through trees, wires, etc., accurate control of the position of the free end of the ladder is quite essential. To meet both of these conditions, I provide a set of reduction gears 24 enclosed in a housing 23, on one end of the shaft I9, and I attach a hand wheel 2t to a driving shaft 21 of said gear train, so that the ladder may be easily rotated to its proper position.

To provide means for automatically locking the hand wheel 26, and hence the ladder, in any desired position, I have developed the new and improved lock shown in detail in Fig. 6. As shown therein, the hand wheel 26 is keyed or otherwise attached to a shaft 21 extending through the outer wall of the gear housing 25, and the hub of the wheel, which extends a short distance along the shaft towards the housing, is provided with splines on its outer surface. A floating collar 29 rides on the hub and engages said splines, and is provided with an interior shoulder 30 fitting around the shaft 21. A helical spring 3 I, bearing against the inner face of the hub of the hand wheel 26 and against the shoulder 30 of the collar urges the floating collar toward the gear housing 25. Solidly connected to the housing wall 25, and surrounding the shaft`21, is a crown gear 28 with its teeth extending outwardly. The inner face of the floating collar is provided with gear teeth similar to those of the crown gear 28, and adapted to mesh with them, so that the collar may be engaged and non-rotatably held by the crown gear 28. An annular groove 32 in the periphery of the floating collar 29 provides means for gripping the oating collar, so that it may be moved outwardly against the urging of the spring 3|.

To accomplish this, I prefer to provide the hand wheel 26 with a handle 33 extending in a direction parallel to the shaft 2'I; and by forming the handle with an axially-extending shank A34 somewhat longer than the diameter of the rim of the wheel, and then passing the shank through the rim, I am able to move the handle in a direction parallel to its axis. At its free end, the shank 34 bears against one end of a rod 35 which is pivotally attached to the wheel 26 at a point 36. At its other end, the rod 35 is provided with a yoke which engages the groove 32 of the floating collar 29, whereby the floating collar may be moved outwardly to disengage it from crown gear 28. Thus, when the wheel lock is in its normal position, the spring 3|, bearing against the inner end of the hub of the wheel 26 and against the shoulder of the lloating collar 29, forces the collar against the crown gear 28, preventing the collar from rotating. Since the collar 29 is provided with internal splines which engage the external splines on the hub of the wheel 26, the

wheel itself is prevented from rotating; and inasmuch as the oating collar 29 is continuously urged towards the crown gear 28 by the spring 3|, the lock is entirely automatic. In this position, the yoke end of the rod is likewise urged toward the gear housing 25, and the outer end of the rod is urged away from the housing, forcing the handle 33 outwardly. If the handle 33 is now pressed inwardly toward the housing 25, the floating collar 29 under the influence of the yoke of the rod 35 will be forced away from the crown gear 28, against the urging of the spring 3|, and moving outwardly along the splines, will be disengaged from the crown gear 28 and permit the hand wheel 26 to be rotated. Thus it is seen that unless the handle 33 is pushed inwardly, the gear wheel is locked in its existing position; and blows, vibration, or falling objects cannot unlock it.

While I have shown and described this wheel lock as it may be applied to my improved ladder hoist, it will be apparent that it is not restricted to that particular adaptation, but may be used in many other applications, as for example to lock the steering or tiller wheel of a boat, to mention only one of numerous uses.

Returning now to the hoist itself, as the boxframe I2 is raised or lowered, the racks I8 and |8a pivot about their point of connection to the swivel links I 'I and Ila. As the box-frame I 2 is lowered, the racks I8 and I 8a move toward a horizontal position, but inasmuch as the shaft I9 is some distance above the point about which the racks pivot, the latter will remain extended a considerable distance above the `bed II unless additional means are provided to lower the racks. I have provided 'such means in my improved form which take the form of swivel links I1 and Ila, designed to permit the lower ends of the racks I8 and |8a to be raised so that the upper 'ends may be lowered to a position nearer the bed I I.

As shown in Fig. 5, if the hand wheel 26 is turned in a direction to lower the ladder after the latter has assumed a horizontal position, the racks I8 and |8a are urged upwardly, since the box-trarne member I2 can go no lower. The

lli

'bedIL racks I8 and |8a, however, are attached to the swivel links I'I and IIa and these restrain the motion of the racks, so that as the hand wheel 26 is rotated, the racks pivot about the gears 20 and 20a. Hence, as the swivel links and IIa swing upwardly, they allow the lower ends cf the racks I8 and |8a to be raised, thus lowering the upper, free end of the racks. In this way, the racks I8 and |8a may be brought to a position more nearly horizontal, a great convenience when transporting the equipment and working around it.

Since it is essential that the ladder be rigidly held when in its extended position, it is necessary for the swivel links I'I and IIa to be held stationary when the ladder is raised. In order to hold the swivel links I'I and I1a and prevent their movement while the ladder is raised, I have provided the lock means shown in Figs. 7 and 8. As illustrated there, the box-frame I2 when in its horizontal position rests on a vertical plunger 40 which extends upwardly from a housing 4I attached to the bed II. Ihe lower end of the Vertical plunger 40 is bevelled, so that a vertical section taken in a plane perpendicular to one side of the box-frame I2 will show the lower end of the plunger sloping downwardly and outwardly toward the side of the bed I I.

A horizontal plunger 42 likewise ts within the housing 4I and is provided with a vertically-positioned axial slot so that the vertical plunger 40 may extend through its central portion. The end of the slot adjacent the bevelled base of the plunger 40 is also bevelled, so that when the vertical plunger is pressed downwardly, the horizontal plunger is forced inwardly into the housing 4I. A small spring 44, bearing against the housing 4| and against the horizontal plunger 42, urges the latter outwardly and, because of their inter-related motions, forces the vertical plunger 40 upwardly. To prevent any possibility of the vertical plunger being thrown completely out of the housing 4|, I prefer to provide a step portion or lip 45 on the lower end of the vertical plunger which Will engage the lower surface of the horizontal plunger 42 and arrest the upward motion of the vertical plunger.

The housing 4| is located adjacent the swivel link I'Ia so that when the latter is lying horizontally on the bed II, the horizontal plunger 42 may extend and bear against the upper face of the link or the fastening means used to connect the link to the rack I 8a. When the box-frame I2 is in the lowered or horizontal position, it rests on the vertical plunger 40, pressing it downwardly and thus retracting the horizontal plunger 42 to a position within the housing 4I, so that the swivel link I'Ia is free to rotate about its point of attachment to the upstanding ear I6a. A similar lock 4Ia is likewise provided at the other side of the box-frame I2 to lock the swivel link I'I in a horizontal position when the ladder is raised.

Assuming that the racks I8 and |8a have been lowered to their lowest position, if the hand wheel 26 is now turned in a direction to raise the ladder, the racks will Il rst be raised to operative position by reason of the swivel links I1 and IIa assuming a horizontal position resting on the Since the box-frame I 2 is in a horizontal position and is bearing against the vertical plunger 40, the horizontal plunger 42 is retracted, and the swivel links are free to assume their horizontal position. Once this has been done, however, further rotation of the hand wheel 26 causes the box-frame l2 to be raised; and since it then no longer bears on the vertical plunger All, the latter moves upwardly and the horizontal plunger 42 moves outwardly to engage and lock its corresponding swivel link in its horizontal position, preventing any possibility of its rotation when the ladder is extended.

To provide means for rotating the ladder when it is raised, I have provided the simplied apparatus shown in Figs. 1, 2, and 3. In my copending application, because of the arrangement of the various parts, it was impossible to make use of so simple an arrangement, and recourse was had to a series cf shafts and gears which, while producing the desired result, introduce additional frictional losses and back-lash. In my new preferred form, I have simplified the former somewhat complicated arrangement and substituted for it the single angularly-positioned shaft 53 with a hand wheel 5l attached to its upper end, which is preferably provided with a wheel lock similar to that previously described. The lower end of the shaft 5U is provided with a bevelled pinion 52 which engages a bevelled gear 53 attached to the stationary frame lil. To rotate the ladder to any desired position, it is only necessary to turn the hand wheel 5| until that position is reached, and upon releasing the locking handle 54, the ladder is locked in that position. The motion is produced by reason of the fact that the gear 53 is rigidly attached to the frame lil which is attached to the truck, while the pinion 52 and its associated shaft 59 are attached to the bed Il of the ladder hoist, and rotate it and the ladder with them. In this way, I have provided simple means for rotating the ladder and locking it any desired position.

It will now be seen that I have provided an improved ladder hoist which may be quickly and easily raised and rotated to any desired position and locked there without the necessity of setting auxiliary locks. In addition, the racks I8 and I 8a may be raised and lowered to operative position without the need for reversing the direction of rotation of the ladder-elevating hand Wheel 26, as was necessary in the hoist disclosed in my copending application.

Having now described and illustrated one form of my invention, I wish it to be understood that my invention is not to be limited to the specific form or arrangement of parts herein described and shown, or specifically covered by my claims.

I claim as my invention:

1. A device of the character described, which includes: a bed; ladder-supporting means pivotally attached to said bed; a swivel link pivotally attached to said bed; a rack pivotally attached to said swivel link; and gear means attached to said ladder-supporting means adapted to cooperate with said rack to rotate said laddersupporting means.

2. A device as described in claim 1 which includes a latching device releasable through the raising of said ladder-supporting means and operable to secure said link from movement.

3. A device of the character described which includes: a rotatable bed; ladder-supporting means pivotally attached to said bed; a swivel link, one end of which is pivotally attached to said bed; a rack member pivotally attached to the other end of said swivel link; gear means attached to said ladder-supporting means and engaging said rack; a second gear means having a mechanical advantage of greater than one connected to said irst gear means; and locking means to automatically hold said first gear means in any desired position.

l. A device as described in claim 3 which is provided with a swivel link lock which includes: a housing attached to said bed; a vertical plunger in said housing having a bevelled lower end surface, and adapted to be contacted and forced downwardly by said ladder-supporting means when said ladder-supporting means is in its lowest position; a horizontal plunger having a centrally-disposed slot through which said vertical plunger is adapted to move, one end of said slot bearing against said bevelled end of said vertical plunger so that said horizontal plunger is retracted within said housing when said vertical plunger is pressed downwardly; and spring means urging said horizontal plunger outwardly, said horizontal plunger being adapted to lock said swivel link when said horizontal plunger is extended outwardly.

5. A device as described in claim 1, including a spring-actuated plunger movable to engage and secure the swivel link when the ladder-supporting means is rotated upwardly, and a rod engageable by said means in its downward movement and arranged to retract said plunger to release said swivel link.

6. A device of the character described, comprising a rotatable bed, a ladder-supporting frame pivotally attached to said bed, a shaft rotatably mounted in said fra-me, a gear keyed to said shaft, a swivel link having one end pivotally connected to said bed, a rack member pivotally connected to the other end of said swivel link and in meshed engagement with said gear, and means to actuate said shaft to raise and lower one end of said frame.

7. A device as described in claim 6, including means for securing said swivel link against movement during the operative movements of the frame.

8. A device as described in claim 6, including means for securing said swivel link against movement during the operative movements of the frame, said means comprising a spring-actuated plunger extensible to engage and secure the swiv-9 el link when the frame is raised and a rod engageable by the frame in its depressed condition and arranged to retract said plunger to release said swivel link.

9. A device of the character described, comprising a bed, a ladder-supporting frame pivotally connected at one end to said bed, a gear rotatably mounted in said frame, a rack in mesh with said gear, a link pivotally connected at its opposite ends to said bed and to said rack, and means to rotatably actuate said gear whereby said frame may .be supported in various tilted positions on said rack.

10. A device as described in claim 9, including means for securing said link connections against movement when said frame is raised into tilted position.

1l. A device of the character described, comprising a bed, a ladder-supporting frame pivotally connected at one end to said bed, a gear rotatably mounted in said frame, a rack in mesh with said gear, a link pivotally connected at its opposite ends to said bed and to said rack, means to rotatably actuate said gear whereby said frame may be supported in various tilted positions on said rack, and locking means to lock said gear in any desired position.

MONTE E. HOVER. 

